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MathNet 2020 — Math Olympiad Vault — Part 01 Question 87

Math Olympiad Vault · MathNet 2020 — Math Olympiad Vault — Part 01

Question 87

Let $A$, $B$, $C$, $P$ and $Q$ be five pairwise different points in the plane. Suppose that $A$, $B$ and $C$ are not collinear and that
$$
\frac{AP}{BP} = \frac{AQ}{BQ} = \frac{21}{20},
$$
$$
\frac{BP}{CP} = \frac{BQ}{CQ} = \frac{20}{19}.
$$
Prove that the line $PQ$ contains the circumcentre of the triangle $ABC$.